The present invention relates to a magnetic head having a magnetoresistive device, e.g., of a giant magnetoresistive type or a tunneling magnetoresistive type.
In recent years, higher recording density has been progressed rapidly in magnetic disk writing/reading apparatus along with increase in the amount of information to be processed. For this purpose, it is an essential technical subject to reduce magnetic spacing, which is a distance between a magnetic head and a magnetic disk. However, as the flying height of the magnetic head decreases, it increases a possibility that a magnetic slider comes into contact with or collides against a magnetic disk surface rotating at high speed. Then, it is necessary that a protection film formed on an air bearing surface of the magnetic head slider is thin and tough, and has high wear resistance. On the other hand, since the magnetoresistive device constituting the magnetic head slider has a disadvantage in which the magnetic material tends to corrode or erode, it is necessary that the air bearing surface protection film also has a function of preventing corrosion of the magnetic material. Further, when a potential difference is formed between the magnetic head and the magnetic disk, electric discharge is generated between the magnetic head and the magnetic disk to destroy the magnetoresistive device. Therefore, the air bearing surface protection film has also been demanded to prevent such electric discharge. To cope with such requirements, a thin protection film has been demanded which does not leave dusts during sliding movement, has low friction coefficient, is excellent in wear resistance, has high density of atoms and thus is dense, and also is chemically stable. Carbon based thin films have often been used since they can satisfy the above requirements to some extent.
As described above, the air bearing surface protection film is formed on the air bearing surface of a magnetic head slider, and flaking of the air bearing surface protection film remarkably decreases mechanical wear resistance and chemical corrosive resistance. Accordingly, a silicon film or the like is located at the lowermost layer of the air bearing surface protection film at present so as to improve adhesion between the air bearing surface protection film and the air bearing surface.
For example, Japanese Patent Laid-open No. 10-188506 describes a magnetic head slider protection layer comprising a silicon adhesion layer and an upper layer coated on the silicon adhesion layer and containing at least silicon and oxygen or at least silicon and nitrogen disposed on an air bearing surface and an electromagnetic conversion device end face of the magnetic head slider.
Further, Japanese Patent Laid-open No. 9-21284 (Japanese Unexamined Patent Application No. 9-21284) describes a magnetic head slider protection film formed of a film containing at least two layers of a silicon film as an adhesion layer and a carbon layer as a protection film in which the silicon layer contains nitrogen.